Improvement in projectiles for ordnance



I. G. BUTLER.

Prefect He for flmnance.

Patented March 9,1875.

' Jon-n e. BUTLER, or new YORK, N. Y.

IMPROVEMENT IN PROJECTILES FOR ORIJNANCE.

Specification forming part of Letters Patent No. 160,569, dated March 9,1875, application filed November 23, 1874.

To all whom it may concern:

Be it known that I, JOHN G. BUTLER, of the city of New York, county ofNew York and State of Sew York, have invented certain Improvements inProjectiles for Rifled Cannon, of which the following is a full andexact description, reference being had to the accompanying drawings, inwhich corresponding letters denote corresponding parts.

It has been found practicable to give rotation to elongated projectilesby causing them to take the riding by means of a cup or saucer shapeddevice, which is forced by the gases of discharge over the base of theprojectile, which is arranged in a conical form, so as to facilitatesuch action. This character-of projectile has heretofore been open toserious objections; First, the power necessary to force thesolid ring ofmetal throughout its entire width, with the unyielding base of theprojectile under it, into ,the groove is so enormous that a full andfair impression of the riding upon the cup or sabot cannot be obtainedwithout a powerful and dangerous wedging strain uponthe gun; and,

' secondly, obliged to forego the advantage of a full and perfectimpression of the riding, there is an undue escape of gas over theprojectile through the unfilled grooves, and a hurtful shearing actionupon the edges of the bands.

The object ofi'this invention is to remedy these difiiculties; and itconsists in reducing the area of that portion of the sabot which isbrought into contact with the'rifling, thereby insuring its more readycompression, and also in providing an additional guaranty to this end bycombining with the wedging cup ancxpansive device which shall readilyfill the grooves and close windage by the expansive efl'ort of thegases-0f discharge.

In the accompanying drawings, Figures I, II, and III represent partiallongitudinal sections and elevations of projectiles with my im provedsahot attached.

Ineach of these figures, which are simple modifications of the sameprinciple, A is the iron body of the projectile. B is the cup-shapedsabot fitted upon the base of the same. This sabot should be of brass,copper or suitable ductile material. d, d, and d are ribs or re-enforcesof metal encircling the'cyliudrical surface of the sabot, and flush withthe exterior cylindrical surface of the projectile. These ribs may becast upon or formed by simply cutting circular grooves around the sahot.c and 6 show, in cross-section, an annular groove or channel made in thebase of the sabot, thus dividing it into an upper lip or flange, o, anda lower lip, p.

The action of this projectile is as follows: When the gun is dischargedthe sabot is driven up the conical base of the projectile, therebywedging the ribs d, d, and d into the riflin g. At the-same time thegas, findingentrance into the annular groove 0, expands the upper lip 0yet more perfectly into the grooves, while the pressure upon the lowerlip or base of the groove, 1), forces the sabot into tight contact withthe projectile at U.

I do not claim as my invention the cupshaped wedging-sabot B, nor do Iclaim the annular groove e, which divides the otherwise solid base intoupper and lower ex'pansible portions, and which is substantially shownin Letters Patent No. 119,313, to me granted in 1871.

What I claim as my invention, and desire to secure by Letters Patent,isv The combination of the ribs d, d, and d and the annular groove 0with the cup-shaped sahot B, substantially as and for the purposehereinbefore set forth.

- JOHN G. BUTLER.

